1. Field of the Invention
This invention relates to a method for producing a permanently-magnetic molding, made from a polymeric support material filled with magnetic filler materials of silicon caoutchouc, hot-vulcanized from at least one starting material.
2. Discussion of Related Art
After being magnetized, permanently-magnetic moldings retain magnetization over an extended period of time, so that metal alloys of iron, nickel and aluminum with the addition of cobalt, manganese and copper, or ceramic oxide materials, are often employed. It is also possible to produce magnets by sintering processes from so-called rare earths such as, for example, cobalt-samarium or neodymium-iron-boron. An alternative way of proceeding when producing permanently-magnetic moldings is by embedding magnetic filler materials into a polymeric support material, wherein the magnetic filler materials are introduced at a high fill rate into the polymer matrix of the support material in the form of small particles and are then accessible to magnetization. The advantage of such magnets provided with a polymeric support material lies in their simple large-scale technical production, while such magnets can also have more complex shapes.
It is, for example, possible to produce such moldings in an injection-molding process from polymeric support materials filled with metallic filler materials, as described by European Patent Reference EP 0 298 764 B1, for example.
Various plastics are suitable as polymeric support materials, such as polyamides, polyolefins, and the like.
It is known from German Patent Reference DE 10 2004 041 746 A1 to provide a caoutchouc mixture, for example on the basis of silicon caoutchouc with a non-magnetic filler material and at least one nano-sized magnetic filler material, and then to expose this caoutchouc mixture to an alternating magnetic field, in particular microwave radiation, to cause heating and shaping of the molded body. A more efficient production method for producing a permanently-magnetic molding on the basis of silicon caoutchouc cannot be derived from German Patent Reference DE 10 2004 041 746 A1.
It is known to hot-vulcanize silicon caoutchouc, including two silicon caoutchouc components as the starting material, in an injection mold and to thus produce a molded body, as taught by European Patent Reference EP 1 293 323 B1, for example. However, no addition of magnetic filler materials and/or magnetization for producing molded magnetic bodies is provided.